Temperature compensator for electrical regulators



W. G. NEILD Jan. 11, 1949.

TEMPERATURE COMPENSATOR FOR ELECTRICAL REGULATORS Filed March 20, 1945ATTORNEY f Patented Jan. 11, 1949 UNITED STATES PATENT OFFICETEMPERATURE COMPENSATOB FOR ELECTRICAL REGULATORS 4 Claims. 1

The present invention relates to electrical regulating apparatus andmore particularly to a novel temperature compensating means for suchapparatus, together with novel means for adjustingthe magneticcharacteristics of the apparatus.

An object of the invention is to provide novel means acting directlyupon a core of an electromagnetic winding for compensating for variancesin the electromagnetic characteristics of the device due to changes intemperature.

Another object of the invention is to provide novel means for adjustingthe core of the elec tromagnetic winding for varying the electromagneticeflect' upon the armature operated thereby.

Another object of the invention is to provide novel manually adjustablemeans whereby the relationship between the spring and electromagneticforces may be varied so as to impart a drooping or rising controlledcurrent or voltage characteristic to the regulator.

These and other objects and features of the invention are pointed out inthe following description interms of the embodiment thereof which isshown in the accompanying drawings. It is to be understood, however,that the drawings are for the purpose of illustration only, and are notdesigned as a definition of the limits of the invention, reference beinghad to the appended claims for this purpose.

Figure l is a sectional View of a regulator embodying one form of theinvention.

Figure 2 is a fragmentary view illustrating an adjusted portion of thecore.

Figure 3 is a modified form of the invention.

Referring to the drawing of Fi ure 1, there is provided a bottom plate Ion which is mounted a casing 2. The bottom plate I and easing 2 areformed of a suitable ferr c-magnetic material. Screw threadedly engagedin the bottom plate l and projecting into the casing 2 is a cylindricaliron core member 5 which cooperates with a top tapered portion 6 of thecasing 2 in providing a variable leakage magnetic path.

About the core member 5 is wound the electromagnetic winding 1,preferably of a suitable copper wire. Positioned on the casing 2 is anannular member I! which is fastened to the bottom plate I by suitablescrews I2, one of which is shown in the drawing.

A housing of a type such as shown in the copending application SerialNo. 570,002, filed December 2'7, 1944, now Patent No. 2,427,805, is-

sued September 23, 1947, is fastened to the annular member 10 b screwsit one of which is shown. in the drawing. Mounted Within the housing 20,as shown in greater detail inthe aforenoted application, is anon-conducting tube of a suitable refractory material such porcelain.The tubular member 25 carries carbon discs forming a carbon ile. Acont-actor member is positioned between one end of the carbon pile 3i!and an armature plate 36. The contactor member 35 is positioned in a cupshaped securing member 40, mounted on the armature 36. The carbon pileis connected so as to regulate a suitable electric circuit in responseto energization of the electromagnetic winding 7.

The armature plate 36 is positioned at one side of a leaf spring 45. Atthe opposite side of the leaf spring is Positioned a second armatureplate 48 and the leaf spring 45 is clamped between the armature plates35 and 48. The leaf spring 45 may be of a type such as shown in thecopending application Serial No. 570,002, filed December 27, 1944, nowpatent No. 2,427,805, icsued. September 23, 1947, or may be of a typesuch as shown in the copending application Serial No. 583,812, filedMarch 20, 1945, now Patent No. 2,427,806, issued September 23, 1947,wherein the force exerted by the leaf spring on the carbon pile 30 isvaried so as to eiiect basic correspondence with varying magnet pullresults. The lat ter arrangement is fully described and claimed in theaforenoted applications and therefore a detail description of the sameis not deemed necessary in the present application.

The cylindrical core member 5 is formed of a suitable iron bearingmaterial and may be adjustably screwed into the bottom plate 5. Theouter end 8 of the member 5 may be formed of a hexagonal shape wherebythe same is adapted for convenient adjustment.

Positioned within the cylindrical core member 5 is a field-adjustingmale screw member 50 pref erably formed of a stainless steel. The screwmember 50 is engaged in screw threads formed within the cylindricalmember 5 so that by turning the. screw member 50 the same may beadjusted' axially within the cylindrical member 5. The outer end 5| ofthe screw member 5 3 may have a hexagonal shape, whereby the same isreadily adapted for convenient adjustment.

The screw member 5!! has formed therein an axially extending bore 56 inwhich there is positioned' an aluminum rod 60 which has the low endportion secured in the screw member 50.

The upper end portion 66 of the aluminum red I is secured in an ironcore member 68 having a bore portion 69 in which is likewise positionedthe aluminum rod 60.

Upon an increase in temperature the aluminum rod 68 expands in relationto the iron cylinder so as to push the iron core member 68 upward so asto decrease the airgap between it and the armature plate 48 and therebyincrease the electromagnetic pull on the armature plate 48.

As the electromagnetic winding 7 tends to heat up the resistance of thecopper wire forming this winding tends to increase and, with constantcurrent or voltages, the ampere turns fall ofi so that the downward pullof the electromagnet 1 on the armature plate 48 would normally tend todecrease, whereupon if uncompensated the leaf spring 45 would tend tomove the contact 35 towards the carbon pile 30 and further compressingthe same so as to decrease the resistance thereof.

However, with the novel aluminum rod 60 provided herein it will be seenthat the changes in the length of the same will cause a variance in themagnetic forces acting on the armature plate 48 so as to compensate forchanges in the resistance of the copper wire of the electromagneticwinding 1.

Moreover, as shown in Figure 2, the magnetic characteristics of thedevice may be altered as required to take up the slack of manufacturingtolerances in the leaf spring 45' and to vary the magneticcharacteristics of the device in relation to the spring force. This maybe done by varying the relative positions of the cylindrical iron core 5and inner iron core 68 in relation to the tapered top plate 6. Thus byproperly adjusting the relationship of the cores 5 and 68, the magneticleakage between the cores and taperedotop plate 6 may be varied withoutvarying the air gap between the core 68 and armature plate 58. Similarlythe magnetic saturation of the core 58 may be varied without changingthe air gap between'the core 58 and the armature plate 48.

The advantage of the latter arrangement over that of a core which may beadjusted bodily in relation to the armature lies, of course, in the factthat the air gap between the inner core 63 and armature plate 48 may beretained constant, while merely the leakage and saturation of the ironcore 58 is changed through adjustment of the outer cylinder core 5.

In a carbon pile regulator of the type described, if the combined forcesexerted by the spring 45 and carbon pile 35 decreases at a rate lessthan that of the counteracting forces exerted by the electromagnet l asthe air gap between the armature 48 and core 68 increases, there will bea resultant rise in the value of the current or voltage controlled bythe carbon pile resistance 30 in response to the electromagnet 1.

Further, if the combined forces exerted by the spring 45 and carbon piledecreases at a rate greater than that of the counter-acting forcesexerted by the electromagnet as the air gap between the armature 48 andcore 68 increases there will be a resultant droop in the value of thecurrent or voltage controlled by the carbon pile resistance 30 inresponse to the electromagnet I.

The operating characteristic then, of the electromagnet i may beadjusted in relation to the combined forces of the spring 45 and carbonpile 4 and saturation of the core 68 through the adjustment of the cores5 and 68 in relation to the tapered portion 6 of the casing 2, aspreviously described.

In Figure 3, there is shown a modified form of the invention, in whichlike numerals indicate like parts to those shown in Figure 1. In thelatter form of the invention the end 10 of the core 68 is formed with atapered portion H which is adapted to fit in a seat, portion formed atthe inner end of the cylindrical member 5.

It will be seen moreover, that in the latter arrangement the face of thecore 68 through which magnetic lines of force act upon the armature 30so as to provide as desired, either a drooping or a risingcharacteristic to the regulator. This may be accomplished by adjustingthe leakage plate 48 remains constant and that adjustment of the core 88in response to the temperature change effects the air gap between thearmature and core 68, the magnetic leakage through the casing 2, and thesaturation of the core 68 as previously explained. Likewise manualadjustment of the cylindrical core 5 will effect a similar result.

Although only two embodiments of the invention have been illustrated anddescribed, various changes in the form and relative arrangements of theparts, which will now appear to those skilled in the art, may be madewithout departing from the scope of the invention. Reference is.therefore, to be had to th appended claims for a definition of thelimits of the invention.

What is claimed is:

1. An electrical regulator comprising a variable resistance element, anelectromagnetic winding, a spring biased armature operated by saidelectromagnetic winding for regulating said variable resistance element,a cylindrical core, means for adjustably mounting the cylindrical corerelative to said electromagnetic winding, said cylindrical core formedof an iron bearing material, a second core formed of an iron bearingmaterial slidably mounted in said cylindrical core and positioned inspaced relation to said armature, a member adjustably mounted at theouter end of said cylindrical core, a rod positioned between said memberand said second core and formed of a material having such a greatertemperature coefiicient of expansion than that of the material of thecylindrical core that the elongation of said rod causes the position ofsaid second core to vary with temperature, and said cylindrical coreadjustable for changing the magnetic leakage of said second core to varythe control characteristic of the regulator independently of the air gapbetween said second core and the armature.

2. An electrical regulator comprising a variable resistance element, anelectromagnetic winding, a spring biased armature operated by saidelectromagnetic winding for regulating said variable resistance element,a cylindrical core projecting into said electromagnetic winding andformed of an iron bearing material, means for adjustably mounting thecylindrical core relative to said electromagnetic winding, a second coreformed of an iron bearing material slidably mounted in said cylindricalcore and positioned in spaced relation to said armature, saidcylindrical core having a tapered seat portion formed at the inner endthereof, said second core having a tapered portion formed at an endadjacent said seat portion and adapted to fit within said tapered seatportion, a member screw threadedly engaged at the outer end of saidcylindrical core, a rod positioned between said member and said secondcore and formed of a material having such a greater coefiicient ofexpansion than that of the cylindrical core that the elongation of therod causes the position of said second core to vary with temperature,and said cylindrical core adjustable for changing the magnetic leakageof said second core to vary the control characteristic of the regulatorindependently of the air gap between said second core and the armature.

3. An electrical regulator comprising a variable resistance element, anelectromagnetic winding, a spring biased armature operated by saidelectromagnetic winding for regulating said variable resistance element,a cylindrical core projecting into said electromagnetic winding andformed of an iron bearing material, a second core formed of an ironbearingmaterial slidably mounted in said cylindrical core and positionedin spaced relation to said armature, a member formed of a ferro magneticmaterial and forming part of a magnetic circuit, said member having aportion positioned in spaced relation to the inner end of saidcylindrical core and said second core, means for adjustably positioningthe relationship of one of said cores to said inwardly projectingportion separately from the other, so as to vary independently of theair gap between the other of said cores and said armature the effectivemagnetic force acting upon said armature by varying the magnetic leakagebetween the member and said cores.

4. An electrical regulator comprising a variable resistance element, anelectromagnetic winding, a spring biased armature operated by saidelectromagnetic winding for regulating said variable resistance element,a cylindrical core projecting into said electromagnetic winding andformed of an iron bearing material, a second core formed of an ironbearing material slidably mounted in said cylindrical core andpositioned in spaced relation to said armature, a casing for saidelectromagnetic winding formed of a ferro magnetic material and having atapered orifice, the inner end of said cylindrical core and second coreprojecting into said tapered orifice, manually operable means foradjusting the cylindrical core in relation to said tapered orifice so asto vary the efiective magnetic force acting upon said armature, andmanually operable means for adjusting said second core in relation tosaid cylindrical core so as to maintain the air gap between said secondcore and said armature substantially constant upon adjustment of saidcylindrical cor-e in relation to said tapered orifice to effect initialfine adjustment of the magnetic leakage between the cores and easingwithout varying the air gap between said second core and armature.

WILLIAM G. NEILD.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,425,858 Hunt Aug. 15, 19222,336,523 Allen Dec. 14, 1943 2,354,542 Rady July 25, 1945 2,387,127Dodd Oct. 16, 1945

